1. Field of the Invention
The present invention relates to an impedance control circuit and, more particularly, to control circuits to adjust a circuit component impedance based, at least in part, on the impedance of an external coupling.
2. Background Information
Circuitry to interface between components of a digital system, such as for a microprocessor system or a server system, for example are well-known. However, increasing signal speeds, such as on the order of 500 megabit transfers per second, have made these interface circuits increasingly complex. For example, due to increasing signal speeds, it may be desirable to match impedances between components of the system, such as between a transmitting amplifier and a controlled impedance signal coupling in a server system, to reduce the amount of signal reflection that may occur.
Impedance control circuits, such as described above, are well-known. However, it would be desirable to have an economic on-chip implementation of a feedback control circuit in which the circuit impedance being adjusted or controlled may be updated even while digital signal samples are being transmitted via the interface circuitry.